He was part of the 101st Airborne Division in Fort Campbell, Kentucky.

"We're paying back," Robert Smith of the Patriot Guard said. "We're paying back what we owe to men like Specialist Walker. Like I said, it's the least we could do for them. He made the ultimate sacrifice. This is what we can do, but we wish we could do more."

Walker's funeral will be held Monday morning at Manchester United Methodist Church, followed by a burial at Jefferson Barracks.

Gov. Jay Nixon has ordered that all of the state's flags be flown at half-staff on Monday.